Valve mechanism for liquid pressure control systems



J fi, 27, 1942, s. MacD. PARKER VALVE MECHANISM FOR LIQUID PRESSURECONTROL SYSTEMS Original Filed Jan. 22, 1938 2 Sheets-Sheet l I IINVENTOR. Sydney MacD. Par/re/ 2 Sheets-Sheet 2 Syd/7e Macfi Par/fer J27 .1942 5. MacD. PARKER VALVE MECHANISM FOR LIQUID PRESSURE CONTROLSYSTEMS ori i al Fil'ed Jan. 22, 1938 ma .0 NK.\W HQ v 1|. m

Q) QM A) Q Q m Q R E W M N? N .U m X Patented Jan. 27, 1942 I VALVEMECHANISM FOR LIQUID PRESSURE CONTROL SYSTEMS Sydney Macdonald Parker,Myton, Warwick, England, assignor' to Automotive Products CompanyLimited, London, England Original application January, 22, 1938, SerialNo. 186,448, now Patent No. 2,244,894, dated June Divided and thisapplication January 4, 1939, Serial No. 249,290. Britain January 30,1937 In Great Claims. (01. 131-153) This invention relates to liquidpressure control systems adapted to be used for operation of aircraftretractable undercarriageafairing doors,

bomb release devices and the like, which are assisted in one directionof their movement by the action of gravity or other external forces.

The gravitational force on these devices may 'well be of such extentthat, if they are allowed to fall freely the sudden arresting of theirmovement at the lowered position may cause a shock suflicient'ly greatto produce undesirable stresses in the aircraft framework, thusnecesitating a heavier and stronger framework than would otherwies berequired. Further, during such a free falling movement, there is atendency for a vacuum to form in the liquid pressure system, whichmay'cause air to be drawn in, thus reductng the efficiency of thesystem.

One object of the present invention is to pro- I vide a liquid pressurecontrol system in which the free fall ofthe'operated member under theaction of gravity or other external forces is controlled or' restricted.

Anotherobject of the invention is to provide I for use in a liquidpressure control system comflow of liquid from said motor when thelatter is' operated in' an opposite direction. I

Yet another object of thev invention is to provide for use-inra liquidpressure control system including a pump having a connection with a,motor, a valveonrsaid connection for restrict.- ing thefiow of liquidfrom said motor in one direction, and means for by-passing said valve inthe event of the resistance offered to said flow of liquidexceeding apredetermined val e. i

Other object and features of the invent on. and other novel combinationsof parts and desirable particular constructions will be apparentcompanying drawings, in which-.

Figure 1 is a diagrammatic view of a liquid glie vallve means showndiagrammatically on 6 Figure 3 shows an alternative embodiment of thevalve means;

Figure 4 shows a further embodiment of valve means, in which isincorporated a pressure operated valve member which permits theby-passing of the heavily loaded valve, and Figure 5 is a section atright-angles to that shown in Figure 4.

Referring to the drawings, Figure 1 shows, diagrammatically, an aircraft.undercarriage comprising a shock absorber leg I pivoted at 2 to thefront wing spar 3 of an aircraft, and a folding strut consisting of twoportions l and 5 extending between the leg I and an attachment point 6on" the rear wing spar I. A liquid pressure operated Jack 8 is mountedbetween the upper part 5 of the strut near the joint l I of the twoparts, and a second attachment point 12 on the rear wing spar I.

The jack 8 is of the double acting type, and is operated by'liquidpressure generated by a pump 13 driven by the engine of the aircraft.The pump it draws liquid from a reservoir I4, and delivers it to aselector valve it, which may be set to connect the pump delivery toeither of two" conduits I6 and II, the former of which leads to theupper end of the jack'8, and so conveys liquid thereto for the purposeof lowering the undercarriage, whilst the latter, l'l, conveys liquid tothe lower end of the jack to raisethe undercarriage. It is of'courseobvious that the. conduit which, during any'particular operation is notdelivering liquid to the jack, is being traversed by liquid returningfrom the lowl8, consistingtof two non-return valves 2|, 22,

opening in opposite directions.

The inlet valve 2| opens when liquid travels from the pump 13 to theJack 8 to raise the from the following description-and from the 945-pressure control system in accordance with my invention, shown inassociation withan aircraft retractable undercarriage;

Figure 2 is a section on an enlarged scale of 5d undercarriage, theoutlet valve 22 being then held firmly on its seat by the pressure. Thevalve 2| has only a light spring tending to hold it on its seat, andthere is therefore practically no restriction to the flow of liquidventering the Jack to shorten it and produce, retraction of theundercarriage.

The inlet valve 2! is of course 'held on to its'seat when liquid isreturning from the jack tothe reservoir by the conduit l1, and theoutlet valve 22' has to open to allow such liquid to pass. This outletvalve 22 is loaded by a strong spring, so that -a considerable pressuremust be created in the liquid beforethis valve opens. Inretractable.undercarriages, movement from the retracted to the extendedposition is of course assisted by the action of gravity, and the valvemeans according to my invention controls the movement/of theundercarriage when it is being so assisted, to prevent the undercarriagefrom running away from the operating pres? sure. The loading of theoutlet valve may of course be so arranged that the weight of theundercarriage is just suflicient to overcome the resistance, and theundercarriage falls slowly under its own weight, or this valve may be soloaded asentirely to prevent downward move? ment of the undercarriageunder its own weight, it being necessary to create pressure in the upperend of the jack for the lowering operation.

Figure 2 is a detailed view of valve means It! shown in Figure l. Thevalve means isinserted in the conduit H, the two sections of which areconnected to the unions 23 and 24. Thelatter are connected internally bya direct'passage 25 in which is mounted the lightly loaded ball valve2|, co-operating with a seat 26. This valve is "loaded on to theseat 26by a light spring 21 taking its support at 28 on the inner part of theunion 24. On each'side of the valve 2| are connected transverse passages3|, 32, connected by a further bore 33 .parallel to the dire t passage25. In the bore 33 is a valveseat 34, n which seats the outlet ballvalve 22, loaded by a spring 35 the strength of which is selected togive the necessary resistance to lowering of the undercarriage. Thisspring is adjustable by means of an abutment screw 36 locked in positionby a cap nut 31, to vary the loading of the valve.

An alternative form of valve means is shown in Figure 3, consisting of acasing 38 having unions 4|, 42 for connecting it to the conduit. 'll

(Figure 1), and having a chamber 43 in which is movably mounted a plate44.

The two unions 4|, 42 are connected to ports 45 and 46 in the oppositeend walls of the chamber 43, the port 46 connected to the union 42 onthe side of the valve nearer to the jack being of greater area than theport 45. The plate 44 has a central aperture 41 which registers with theport 45, but is of less area than this port, and

a series 'of supplementary apertures 48 arranged around a circle andwhich come within the'area of the port 46 but are outside the area ofthe port 45. The flow of liquid in the conduit causes the plate 44 tobear against the wall of the chamber 43 opposite to that through whichthe liquid is entering. Consequently, when liquid is being supplied tothe jack to raise the undercarriage,

the plate 44 is held against the wall of the chamber 43 containing theport 46, and liquid can flow through all the apertures 41 and 48,-giving a free flow. Liquid returning from the jack to the reservoir whenthe undercarriage is being Ioweredmoves the plate 4.4 into engagementwith the other wall. of the chamber 43; thus shutting off the apertures48, and leaving only the aperture 41 open, and causing a restriction offlow which depends on the area of theaper'ture 41.

The valve/means shown in- Figures 4 and 5 is similar to that shown inFigure 2, but has incorporated therein a by-pass which is opened when apredetermined pressure is reached in the system, to by-pass the heavilyloaded outlet valve,

unions open into parallel passages 34, in'the casing 5|, which passagesare-connected near their ends by cross passages 58, 51. The passage 55contains the lightly loaded inlet valve 58, which is urged towards aseat 6-! by a spring 62 taking its abutment on a plug 63. The passageS'I'contains the heavily loaded outlet valve 64, urged towards its seat65 by a spring 66 whose compression is adjustable by means of a'plunger67 and "screw-threaded sleeve 68, the plungembeing positionedrelatively'to the sleeve 68 by a pin H extending through registeringholes formed in said sleeve.

The pin II provides a releasing device for the outlet valve, removal ofthe pin taking oil? the' load from the spring 66 and so freeing thevalve 64. The primary object of this is to enable the entire removal ,ofthe resistance oflered to the flow of liquid inthe event of failure ofthe engine driven pump, which normally'generates the pres-' sure in thesystem, so that operation by an auxiliary hand pump may be facilitated.

In the'casing 5| formed with passages 54, 55 and passages 53, 51, isformed a bore" having its axis at right angles to the general plane ofthese passages, and a valve member 13, having an .annular groove I4, isslidably mounted in said bore; Ports 15,16 connect the passages 54, 53to the bore 12 at spaced points along its length, and these ports aredisconnected or connected by movement of the valve member 13 in thebore,

said ports'being connected whemboth of them are in register with theannular groove 14. To one end of the valve member I3 is connected apiston 11 fitting in. a cylinder 18 formed by a reduced extension of thebore 12, and the other end of said valve member'is loaded by a spring13,,

adapted to be adjusted by means of a thimble 8| threaded into a sleeve"itself mounted in-the end of the casing 5|.

The operation of this device is similar to that'of the valve meansdescribed with-reference to Figures 1 and 2, the valve member 13 beingnormally in such wposition that the port 15' is disconnected from theport 16. The cylinder 13 is connected by a union 83 and branch conduitto the conduit ii of Figure 1, so that the pressure in that conduitduring lowering of the undercarriage acts on the piston I1, tending tomove the valve member 13 to the right of Figure 5. The spring 19 may beof any selected strength, so that the valve member I3 ismoved when'theload reaches a predetermined-limit to by-pass the out- -let valve 64 andpermit the full pressure generated bythe pump to act on theundercarriage 'fjack.

- and allow the full pressure generated by the pump to be usefullyemployed in the movement of the undercarriage. This by-pass is anextremely desirable feature incases where the whole ex So long as theundercarriage is extending easily, very little pressure exists in theconduit l6, and the outlet valve 64 remains in action to control suchextension.

If however a resistance to extension is met, as for example when theundercarriage reaches a position in which gravity no longer assists itsmovement, the pressure rises until it acts on the a third valve adaptedto by-pass may be necessary at the commencement of the. extension of theundercarriage, for example to said portsin one directionin response tothe pressure of the fluid directed thereto, a second valve permittingflow of fluid through said ports inopposite direction in response tothepressure of the fluid directed thereto, and a third valve fordirectlyconnecting said ports in response to the pressure of confined fluidother than thatfluid which is directed thereto release a look. In thiscase the valve member I3 will be moved to connect the ports 15 and 16'before the undercarriage is released, and as soon as the undercarriageis released and its weight begins to assist the extension, the fall ofpres--' sure in the conduit IE will allow the spring I9 to returnthevalve member I3 to a position in which the port 53 is disconnected fromthe port 52, and the outlet valve will come into action Although thisinvention has been described 3. In a valvehousing having a conduitleading thereto from an external fluid source, and 'a second conduitextending therefrom to a point offluid use, valve means including anon-returnvalve permitting flow from said-first to said second conduit,a second non-return valve permitting flowlback to. said first conduit byway of said second conduit a third valveshiftable to ain connection withcertain specific'embodiments,

the principles involved are susceptible of numer-- ous otherapplications. which 'will readily occur to persons skilled in the art.'-The'inventio'n is,

therefore, to be limited only as indicated by the scope of the appendedclaims.

This application is a-divlsmn of my co-pend ing application No. 186,448,filed January 22,j

1938, now Patent No. 2,244,894, granted June 10.-

What I claim is; 1. A valve means including one valve opening in onedirection in response 'to the-pressure o! 1 said conduitconnectingposition;

fluid directed thereto, and permitting flow .therethrough, another valveopening in opposite di-z motion in response to the pressure. or fluiddirected thereto, and permitting flow therethrough,

second valves, and means for opening said third valve, said openingmeans including an element said first and.

which is subjected to the, pressure of: a body oi fluid other than thatwhich is directed to and flows through-said third valve;

2. Avalve means for connecting two ports in-jposition directlyconnecting said conduits, and means responsive to a pressure-rise ofpredetermined amount, at said'point of use, for shifting said thirdvalve ;-to vsaid conduit connecting,

position.

and means independent of the direction of flow in said conduits forshifting said third valve 5. A'- valve' means including 'two valves,each shiftab l'e, by fluid flow directedthereto, and in the direction orfluid flow, a third'valve shiftable transversely of the direction offlow, to increase the rate of flow beyond the capacity of either of saidfirst-named valves," and means for shift- -ing said third valve, saidshifting means being a independent of the fluid which flows throughsaid-third valve.

SYDINEY mononam BARKER.

cludin g-one va lve permitting flow of fluid through valve housinghaving a conduit'leading thereto from an external fluid source, and asecond conduit extending,therefrom .to a point of; fluid-use, valvemeansg -including a non-return valve permitting,g-fiowjffrom said firstto said" second-"conduit,:zagsecond non-return valvepermitting'zflow'back to said first. conduit .by way I of said-secondconduit,-a third valveshiftable to a position directly connecting saidconduits,

